1. Field of the Invention
The present invention relates to disk loading apparatuses and, in particular, to a slot-in type disk loading apparatus adapted to load a disk inserted through a slot onto a chucking position under the centering action of a feed roller.
2. Description of the Related Art
FIGS. 9 and 10 schematically show the basic configuration of this kind of disk loading apparatus, where FIG. 9 is a schematic configuration view at the beginning stage of loading where a disk 100 is inserted through a slot 1 and FIG. 10 is a schematic configuration view at the termination stage of loading where the disk 100 is loaded and arranged on a chucking position.
In this disk loading apparatus, the normal rotation of a feed roller 2 that is installed in the vicinity of the slot 1 draws the disk 100 inserted through the slot 1 onto the chucking position, while the reverse rotation of the feed roller 2 feeds the disk 100 out of the chucking position to eject through the slot 1. Also, the feed roller 2 is formed in an hourglass shape with a diameter increasing from the center thereof in the axial direction as shown in the drawings. The feed roller 2 is adapted to rotate in contact with one surface of the disk 100 to give the disk 100 a feed force in the drawing and ejecting direction A that is perpendicular to the axis P of the feed roller 2 and to fulfill a centering function of moving the disk 100 toward the center of the feed roller 2 in the axial direction as indicated by the arrow B.
Meanwhile, a disk arm 4 is mounted on the inside of the top of the chassis 3 correspondingly to the feed roller 2. The disk arm 4 is adapted to move back and forth between an initial position (advanced position as shown in FIG. 9) where the disk 100 that is drawn through the slot 1 by the normal rotation of the feed roller 2 is received and a retracted position (as shown in FIG. 10) that corresponds to the chucking position for the disk 100, and the back-and-forth movement is guided by a straight guide groove 5 formed in the chassis 3. Specifically, an elongated convex engaging body 41 formed integrally with the disk arm 4 is engaged slidably with the guide groove 5 that has a uniform groove width over the entire effective length. The engaging body 41 is adapted to slide in the guide groove 5 in the longitudinal direction so that the disk arm 4 moves back and forth between the initial position shown in FIG. 9 and the retracted position shown in FIG. 10.
Between the disk arm 4 and the feed roller 2, there is an installation space 6 for a turntable (not shown in the drawings) attached to the chassis 3 via a motor (not shown in the drawings), and a clamper (not shown in the drawings) is arranged in a position facing the installation space 6. The disk 100 that is drawn onto the chucking position is chucked at a right position by the cooperation of the turntable arranged in the installation space 6 and the clamper, and in this state, the turntable is driven rotationally together with the disk 100.
In addition, the chucking operation for the disk 100 by the cooperation of the turntable and the clamper is interlocked with the retracting operation of the disk arm 4, while the chucking release operation for the disk 100 by the cooperation of the turntable and the clamper is interlocked with the advancing operation of the disk arm 4 via an interlocking system not shown in the drawings.
That is, in a disk loading mode, the turntable and the clamper are in the chucking release position so that the disk 100 is received between them in a retracting step where the disk arm 4 is pushed in from the initial position shown in FIG. 9 toward the retracted position shown in FIG. 10 by the push-in operation of the disk 100 that is drawn by the feed roller 2. Then, a chucking step by the cooperation of the turntable and the clamper begins when the disk 100 is drawn onto the chucking position between the turntable and the clamper and the disk arm 4 arrives at the retracted position shown in FIG. 10. Then, with the beginning of the chucking step, the disk arm 4 is further retracted away from the disk 100, and the feed roller 2 is retracted away from the surface of the disk 100. On the contrary, in a disk unloading mode, with the termination of the step of moving the turntable and the clamper to the chucking release position, the feed roller 2 is brought into contact with the surface of the disk 100 in the chucking position to eject the disk 100 through the slot 1, and then the disk arm 4 is advanced to the initial position shown in FIG. 9 through the retracted position shown in FIG. 10
FIG. 11 is a vertical cross-sectional front view schematically showing the mounting structure of the disk arm 4 onto the chassis 3. As shown in this drawing, the engaging body 41 included in the disk arm 4 is engaged slidably with the guide groove 5 in such a manner as not to jolt heavily, where the engaging body 41 includes a retaining piece 42 for preventing the disk arm 4 from dropping out of the chassis 3, and the disk arm 4 includes disk receiving portions 43 for catching two parts on the outer peripheral surface of the disk 100 that is indicated by the alternate long and short dash line to receive the disk 100. It is noted that in FIG. 11, a common disk receiving portion 43a is provided in one part on one side in the width direction of the disk arm 4, and inner and outer disk receiving portions 43b and 43c are provided in two parts on the other side in the width direction of the disk arm 4. This is for the reason that small-diameter disks (8 cm disks) can be received by a part or all of the common, inner, and outer disk receiving portions 43a, 43b, and 43c, while large-diameter disks (12 cm disks) can also be received by the common and inner disk receiving portions 43a and 43b. Therefore, the exemplary disk loading apparatus shown in the drawing can use both small-diameter disks and large-diameter disks separately.
In disk loading apparatuses having such a basic configuration as described with reference to FIGS. 9 and 10, since both small-diameter disks and large-diameter disks can be used separately, the width of the slot 1 and the length of the feed roller 2 are determined to suit the diameter of large-diameter disks. Therefore, small-diameter disks, in particular, are not always inserted at the center of the slot 1, but often inserted at a left- or right-biased position.
FIGS. 12 and 13 illustrate a centering action for a disk (small-diameter disk) 100 inserted at such a biased position, where FIG. 12 illustrates the positional relationship between the disk arm 4 and the disk 100 and FIG. 13 illustrates interactions between the engaging body 41 and the guide groove 5. The centering action will hereinafter be described with reference to FIGS. 9 to 13.
The disk 100 inserted through the slot 1 at a biased position is drawn in the direction indicated by the arrow A1 in FIG. 12 by the feed roller 2 that rotates normally in contact with the surface of the disk as shown in FIG. 9, and then the outer peripheral surface of the disk runs into only the common disk receiving portion 43a of the disk arm 4 in the initial position and not come into contact with the disk receiving portion 43b or 43c, whereby the push-in operation of the disk 100 is applied to a biased portion of the disk arm 4. Therefore, the disk arm 4 is subject to a torque (indicated by the arrow M in FIG. 12) around the engaging body 41 that is engaged slidably with the guide groove 5, and then as shown in FIG. 13, one end of the engaging body 41 is pressed against one wall surface 51 of the guide groove 5 as indicated by the arrow Ml, while the other end of the engaging body 41 is pressed against the other wall surface 52 of the guide groove 5 as indicated by the arrow M2, resulting in an increase in the sliding resistance of the engaging body 41 against the guide groove 5. This causes the disk arm 4 to be retracted while the disk 100 drawn by the feed roller 2 and the disk arm 4 are pressed against each other, and the centering function of the feed roller 2 during the retracting step causes the disk 100 to move in the centering direction indicated by the arrow B1 in FIG. 12. When this centering action positions the center of the disk 100 on the extension C of the center line of the guide groove 5, the torque M disappears and the centering function of the feed roller 2 is disabled. This shows that the disk 100 can be drawn accurately onto the chucking position shown in FIG. 10 only if the disk 100 and the disk arm 4 are pressed against each other when the disk arm 4 is retracted and thereby the centering function of the feed roller 2 is exhibited normally.
Meanwhile, as for mechanisms of loading optical disks, there has been proposed a technique for correcting the position of a disk by bringing the disk into contact with a tapered shaft (refer to Japanese Patent Laid-Open Publication No. Hei 8-7433 for example). As for the separate usage of 8 cm disks and 12 cm disks in disk players, there has also been proposed a technique in which the position of a centering lever is variable so that the right position of each disk with respect to a turntable can be determined separately based on the operation of the centering lever (refer to Japanese Patent Laid-Open Publication No. Hei 9-44954 for example). There has further been proposed a technique for allowing disk reproducing apparatuses to be thinned even if the disk reproducing apparatuses may employ a structure of using both small-diameter disks and large-diameter disks separately (refer to Japanese Patent Laid-Open Publication No. 2004-46913 for example).
Meanwhile, in accordance with the disk loading apparatus described with reference to FIGS. 9 to 13, the disk 100 can be drawn accurately onto the chucking position shown in FIG. 10, as mentioned above, only if the disk 100 and the disk arm 4 are pressed against each other when the disk arm 4 is retracted and thereby the centering function of the feed roller 2 is exhibited normally.
However, in this disk loading apparatus, since the pressing between the disk 100 and the disk arm 4 during the step of retracting the disk arm 4 depends on the sliding resistance of the engaging body 41 against the wall surfaces 51 and 52 of the guide groove 5, the pressing state may not appear normally if the engaging body 41 is worn away, for example. Alternatively, the pressing state may not also appear normally for some reasons. Therefore, there has been a problem in that even if the feed roller 2 may have a centering function, disks may not be loaded accurately onto the chucking position due to the loss of the stability in the centering operation. Particularly, in the disk loading apparatus capable of using both large-diameter disks and small-diameter disks separately, since the displacement of small-diameter disks for normal centering is greater than that of large-diameter disks, the above-described problem is more likely to occur when using small-diameter disks.
On the other hand, the technique proposed in Japanese Patent Laid-Open Publication No. Hei 8-7433 is achieved by adding extra parts and complicated structures, which cannot improve the stability in the centering operation at low cost. Also, neither of the techniques proposed in Japanese Patent Laid-Open Publication Nos. Hei 9-44954 and 2004-46913 directly concerns the centering of disks.